Vehicle windows (e.g., windshields, backlites, sunroofs, and sidelites) are known in the art. For purposes of example, vehicle windshields typically include a pair of bent glass substrates laminated together via a polymer interlayer such as polyvinyl butyral (PVB). It is known that one of the two glass substrates may have a coating (e.g., low-E coating) thereon for solar control purposes such as reflecting IR and/or UV radiation, so that the vehicle interior can be more comfortable in certain weather conditions. Conventional vehicle windshields are made as follows. First and second flat glass substrates are provided, one of them optionally having a low-E coating sputtered thereon. The pair of glass substrates are washed and booked together (i.e., stacked on one another), and then while booked are heat bent together into the desired windshield shape at a high temperature(s) (e.g., 8 minutes at about 600-625 degrees C.). The two bent glass substrates are then laminated together via the polymer interlayer to form the vehicle windshield.
Insulating glass (IG) windows are also known in the art. Conventional IG window units include at least first and second glass substrates (one of which may have a solar control coating on an interior surface thereof) that are coupled to one another via at least one seal(s) or spacer(s). The resulting space or gap between the glass substrates may or may not be filled with gas and/or evacuated to a low pressure in different instances. However, many IG units are required to be tempered. Thermal tempering of the glass substrates for such IG units typically requires heating the glass substrates to temperature(s) of at least about 600 degrees C. for a sufficient period of time to enable thermal tempering. Monolithic architectural windows for use in homes or building are also known in the art. Again, monolithic windows are often thermally tempered for safety purposes, such tempering involving high temperature during heat treatment.
Other types of coated articles also require heat treatment (HT) (e.g., tempering, heat bending, and/or heat strengthening) in certain applications. For example and without limitation, glass shower door windows, glass table tops, and the like require HT in certain instances.
Diamond-like carbon (DLC) is sometimes known for its scratch resistant properties. For example, different types of DLC are discussed in the following U.S. Pat. Nos. 6,303,226; 6,303,225; 6,261,693; 6,338,901; 6,312,808; 6,280,834; 6,284,377; 6,335,086; 5,858,477; 5,635,245; 5,888,593; 5,135,808; 5,900,342; and 5,470,661, all of which are hereby incorporated herein by reference.
It would sometimes be desirable to provide a window unit or other glass article with a protective coating including DLC in order to protect it from scratches and the like. Unfortunately, DLC tends to oxidize and burn off at temperatures of from approximately 380 to 400 degrees C. or higher, as the heat treatment is typically conducted in an atmosphere including oxygen. Thus, it will be appreciated that DLC as a protective overcoat cannot withstand heat treatments (HT) at the extremely high temperatures described above which are often required in the manufacture of vehicle windows, IG window units, glass table tops, and/or the like. Accordingly, DLC cannot be used alone as a coating to be heat treated, because it will oxidize during the heat treatment and substantially disappear as a result of the same (i.e., it will burn off).
Certain other types of scratch resistant materials also are not capable of withstanding heat treatment sufficient for tempering, heat strengthening and/or bending of an underlying glass substrate.
Accordingly, those skilled in the art will appreciate that a need in the art exists for a method of making a scratch resistant coated article for use in a window or the like that may be capable of being heat treated (HT) so that after heat treatment the coated article is scratch resistant. A need for corresponding coated articles, both heat treated and pre-HT or non-HT, also exists.
Photocatalytic coatings are also sometimes desirable in window applications. Photocatalytic coatings are also known as self-cleaning coatings, where the coating reacts with and decomposes organic compounds or pollutants into inorganic non-harmful compounds such as CO2 and/or H2O.
Accordingly, in certain example embodiments of this invention, it will be appreciated that there exists a need in the art for a scratch resistant coated article having a combination of anti-scratching properties and self-cleaning properties. In certain example instances, it would be advantageous to provide a window that is both scratch resistant and could function in a self-cleaning manner. In still further example embodiments, it would be desirable to provide a window having both photocatalytic functions and anti-fungal/anti-bacterial functions. While coatings herein are often used in the context of windows, they also may be used in the context of table-tops or in other applications in certain example instances.